I finished my little home doll rehab project. Thanks so much for all your suggestions! I decided to go with the idea of making a new cloth torso to slip over the existing cloth body and securing it with a strong fabric glue (except that I didn't trust the fabric glue so I also sewed it to the fabric underneath). I took some photos showing the process:
Here's Maia's doll, "Baby", before rehab. She doesn't look so bad from the front, but the left leg is torn and needs to be sewn and she has already been sewn up around each arm.
Here's the rear view after sewing up a gaping hole in her back. And you can see another hole at the leg and various stitches where she's been sewn before. Did I mention she's been well loved? She was given to Maia by a friend's teenager who was finally ready to pass her on.
For the new body, I chose an organic cotton knit from my stash. My thinking (besides liking the neutral cream color) was that a knit would be more flexible and resilient and less likely to tear in the future. I folded the fabric, set Baby over it with the fold along the shoulders, and traced her body onto the fabric for the general size and shape. Then I cut it out and sewed the sides.
I slipped the new covering over Baby to test the fit. Luckily it fit well on the first try. (By the way, I sewed up all the holes in Baby's body first. Not sure it was necessary, but it felt like the right thing to do.)
I took the covering off and hemmed around the arm and leg holes before slipping it back on.
I sewed the crotch closed by hand. Then, since, as I mentioned above, I didn't fully trust the idea of fabric glue, I also sewed the new fabric covering to the existing fabric at the legs, arms, and neck.
Here's Baby after sewing on her new torso covering.
And, finally, I sucked it up and paid an insane $8 for a little bottle of Fabri-tac fabric glue that I didn't even believe in. I lifted up the edges of the new covering to apply the glue to both the old fabric and to the plastic so that the new covering would be securely glued to both at all openings -- legs, arms, and neck. This stuff works quickly! And seems super secure even after a few minutes. I think I'm a believer now. You could probably put together an entire outfit with fabric and this glue, skipping the sewing machine altogether, and it would hold up.
Here's Baby, missing a couple of eyelashes and with one eye that doesn't always shut properly, but otherwise as good as new and ready to be loved for a few more years. The rest of her body is a little cleaner here, too. I took a toothbrush and a little bowl of warm, soapy water and scrubbed the plastic clean -- something I should have done a long time ago!